Eye Pharm

Question 1

Which is a PDE inhibitor that affects vision?

Answer 1

Viagra

Question 2

Name the 2 opposing muscles (IRIS) that control the opening of the pupil AND their receptors.

Answer 2

1) Pupillary Dilator - ALPHA adrenergic receptor

2) Pupillary Constrictor - muscarinic (M) receptor

Question 3

Name the autonomic receptor on ciliary muscle that controls accommodation and facilitates aqueous humor outflow

Answer 3

Muscarinic (M) receptor

Question 4

Name the autonomic receptor on ciliary epithelium (ciliary body- produces aqueous humor)

Answer 4

BETA adrenergic receptor

Question 5

What two categories of drugs can be used to induce MYDRIASIS to facilitate an ophthalmic exam?

Answer 5

PHENYLEPHRINE (alpha agonist) - to act on pupillary dilator

TROPICAMIDE (anti-muscarinics) - to antagonize pupillary constrictor

Question 6

What class of drugs is used to generate CYCLOPLEGIA (accommodation blockade)

Answer 6

Anti-muscarinics

Question 7

What are the two classes of drugs that can be used to reduce intraocular pressure (IOP)?

Answer 7

MUSCARINIC Agonists - To facilitate AH outflow

CHOLINESTERASE Inhibitors - Same effect

Question 8

Name the three anti-muscarinics

1- prototype, 1- derivative

Answer 8

1) ATROPINE - Prototype
2) SCOPOLAMINE - Derivative
3) TROPICAMIDE

Question 9

Which of the anti-muscarinics can be used as a transdermal patch for motion sickness?

Answer 9

SCOPOLAMINE

Question 10

Describe the pharmacokinetics (Absorption of ADME) of anti-muscarinics.

Answer 10

Both atropine and scopolamine are absorbed from the GUT and CONJUNCTIVA -> Antagonize the ciliary muscle + pupillary constrictor

Question 11

Pneumonic for symptoms of ANTIMUSCARINIC EXCESS

Answer 11

Dry as a bone, Blind as a bat, Mad as a hatter, Hot as hell, Red as a beet, Full as a flask

Question 12

ANTI-MUSCARINIC EXCESS 1:

Dry as a Bone

Answer 12

Decreased sweat, lacrimal gland secretion (tears), and salivary gland secretion (salivation)

Question 13

ANTI-MUSCARINIC EXCESS 2:

Blind as a Bat

Answer 13

Cyclopegia (Ciliary Muscle Paralysis) - Eyes are fixed to far objects -> Can NOT accommodate lens to focus on near objects

Question 14

ANTI-MUSCARINIC EXCESS 3:

Mad as a hatter

Answer 14

Decrease in Ach = CNS Excitation

Restlessness, Irritability, Disorientation, Delirium, Hallucination

Question 15

ANTI-MUSCARINIC EXCESS 3:

Hot as hell

Answer 15

Decreased ability to sweat

Question 16

ANTI-MUSCARINIC EXCESS 4:

Red as a Beet

Answer 16

Decreased ability to sweat -> Cutaneous vasodilation to try to facilitate heat dispersal

Question 17

ANTI-MUSCARINIC EXCESS 5:

Full as a flask

Answer 17

Inability to contract bladder -> Urinary retention

Question 18

How does anti-muscarinic excess affect adults and children?

Answer 18

ADULTS: Not life-threatening
CHILDREN: Life-threatening due to hyperthermia

Question 19

TREATMENT (3) : Anti-muscarinic Excess

Answer 19

1) Cooling blankets
2) Benzodiazapines (DIAZEPAM) - Seizure Control
3) Cholinesterase Inhibitor (PHYSOSTIGIMINE)

Question 20

Why is TROPICAMIDE used as a mydriatic, cyclopegic agent in ophthalmic exams rather than ATROPINE or SCOPOLAMINE?

Answer 20

Tropicamide’s Duration of Effect is SHORTER (4 hrs) as opposed to atropine and scopolamine (7-10days, 3-7days). Do not have to worry about anti-muscarinic excess

Question 21

What eye pathology is ATROPINE particularly useful for? Why?

Answer 21

AMBLYOPIA (Lazy Eye) - Longer Half-life

Induces cyclopegia in STRONGER eye so that brain is forced to use and strengthen the weaker eye

Question 22

What is the ALTERNATIVE, Second line of treatment for amblyopia?

Answer 22

Scopolamine (Patch)

Question 23

Name the two components of SECRETING and FACILITATING aqueous humor outflow.

Answer 23

1) Ciliary Body Epithelium (beta adrenergic receptors) - Secrete AH
2) Ciliary Muscle (M receptors) - Contraction puts tension on TRABECULAR MESHWORK -> Facilitates outflow through the canal of Schlemm

Question 24

Name the two classes of drugs used to treat glaucoma.

Answer 24

1) BETA ADRENERGIC BLOCKERS - ANTAGONIZE AH production by ciliary epithelium
2) CHOLINESTERASE INHIBITORS - AGONIZE ciliary muscle contraction that puts tension on the trabecular meshwork -> Increase AH outflow -> Decrease IOP

Question 25

What is the FIRST line of treatment for gluacoma?

Answer 25

LATANOPROST

Question 26

What is the mechanism of action of LATANOPROST?

Answer 26

Prodrug for PGF2alpha

Acts on prostaglandin receptors -> Increases UVEOSCLERAL outflow of AH

Question 27

What are three classes of drugs that DECREASE Aqueous humor production to combat glaucoma?

Answer 27

1) BETA BLOCKERS - Timolol
2) CARBONIC ANHYDRASE INHIBITORS - Brinzolamide
3) ALPHA-2 AGONISTS - Apraclonidine

Question 28

What are the two classes of drugs that increase uveoscleral outflow to combat glaucoma?

Answer 28

1) LATANOPROST (PGF2alpha prodrug)

2) APROCLONIDINE (alpha-2 agonist)

Question 29

Which two classes of drugs contract ciliary muscle fibers, thereby increasing aqueous humor outflow to combat glaucoma?

Answer 29

1) CHOLINERGIC AGONIST - Pilocarpine/Carbachol

2) CHOLINESTERASE INHIBITOR - Echothiophate, Physostigimine

Question 30

Clarification on UVEOSCLERAL OUTFLOW

Answer 30

90% of aqueous humor drains through angle of the eye -> canal of schlemm -> Venous system
10% follows an unconventional pathway (UVEOSCLERAL OUTFLOW) - Fluid flows through the ciliary muscle -> Suprachoroidal space

Question 31

Which class of drug is used for CLOSED ANGLE GLAUCOMA? Name the two (1 oral, 1 IV) drugs within this class.

Answer 31

OSMOTIC AGENT - Increases osmotic gradient between eye and circulating blood -> Increases fluid efflux
ORAL glycerol
IV mannitol
Acts within 10mins

Question 32

How do topical eye drugs access the systemic circulation?

Answer 32

NASAL ABSORPTION - Lacrimal drainage -> Nose (highly vascular mucosal epithelium) -> Circulation